1. Field of the Invention
The invention relates to a polymerizable liquid crystal composition which is used for optical devices having a liquid crystal molecule tilt-aligned therein, an optical device using this composition, a method of manufacturing this optical device, and a liquid crystal display using this optical device.
2. Description of the Related Art
As an optical device to be built into a liquid crystal display, optical devices made of a liquid crystal material of a polymerization type are known and widely used as an absorption type circular polarizing plate which configures a liquid crystal display (for example, a λ/4 retardation layer and a λ/2 retardation layer), a linear polarizing plate, or a viewing angle compensation layer of various liquid crystal modes.
For example, in liquid crystal displays of an ECB mode, it is known that a wide viewing angle is obtained by providing, as a retardation layer, an optical device with a so-called hybrid structure having a liquid crystal molecule tilt-aligned therein. In manufacturing such an optical device (retardation layer) having a liquid crystal molecule tilt-aligned therein, it is disclosed to use a polymerizable liquid crystal compound as a composition mixed with a photopolymerization initiator and a surfactant and to use, as the photopolymerization initiator, benzoin ethers, benzophenones, acetophenones, benzyl ketals, acyl phosphine oxides, etc. (see, JP-A-2005-272560 (Patent Document 1)).
Also, in liquid crystal displays, it is devised to realize thinning of the display by providing the foregoing retardation layer inside a liquid crystal cell having a liquid crystal layer interposed between two substrates and subjecting it to in-cell processing. As one example of such a configuration that a retardation layer is subjected to in-cell processing, a configuration that retardation layers whose retardation is changed for every pixel of respective RGB colors are provided is disclosed, too (see JP-A-7-199173 (Patent Document 2)).